This invention relates to a sliding deck as a rearward portion of a fixed deck of a flat truck bed in combination with a lowering mechanism for lowering the sliding deck from the fixed deck height to a ground level while maintaining the sliding deck at about a zero degree incline relative to a ground surface to about a minus 15% incline for loading and unloading. More particularly, this invention relates to such a load-bearing sliding deck as an OEM structure in combination with a fixed deck of the flat truck bed. Still more specifically, this invention relates to a sliding deck for carrying goods in transit at a raised level and lowering those goods to a lower or ground level by using tower members having pivoting outer tubular tower members cooperating with mating telescoping internal tubular tower members actuated by hydraulic cylinders located in the interior of the pivoting outer tubular tower members for moving the load-bearing deck upwardly or downwardly. Still more particularly, the sliding deck according to the invention includes a pair of inclined pivoting tower members supported for controlled pivoting by a supporting hydraulic cylinder causing pivoting, the tower members inclined at an angle relative to the truck bed and include a pivoting outer tubular tower member and a sliding interior tubular telescoping member controlled by a hydraulic cylinder contained in the interior of the pivoting inclined tower members and which effectively extends the area of the fixed deck of the truck by an amount defined by the sliding deck. Alternatively, the tower members could be fixed for limited applications on level ground.